(1) Field of the Invention
The present invention relates to a process for detecting defects including poor lamination and fine voids such as cracks present in ceramic bodies, such as laminates of ceramic planar sheets or members and ceramic structural bodies produced by pressing powders.
(2) Related Art Statement
Heretofore, the following techniques have been known as processes for detecting defects in ceramic bodies. For example, after a penetrable liquid containing a coloring matter penetrates fine voids present in a ceramic body, excess liquid attached to the surface of the ceramic body is washed off. As a result, no coloring matter remains attached onto a portion of the ceramic body free from defects, whereas the coloring matter remains on any portions containing defects. Therefore, defects can be detected by visual inspection. Further, a fluorescent paint may be used instead of the coloring matter. In this case, the fluorescent paint is impregnated into a ceramic body, and excess paint is washed off with water. Then, ultraviolet rays are irradiated upon the ceramic body in a dark chamber, so that any defects in the ceramic body can be detected from emission of light from the fluorescent paint impregnated into the defect. In the above techniques, presence or absence of the defect have been judged visually.
However, since the above-mentioned defect-detecting techniques are based on visual inspection, detecting ability depends upon the skill of inspecting individuals, whereby a small defect may be overlooked. Further, visual inspection hinders automation of consecutive steps, resulting in production processes having low productivity.